It's unlikely, but not totally improbable - Model collapse means that the subsequent models would get worse over time, not better.
1. AI free training sets no longer exist. This might degrade quality, although some claim that it will not.
2. Cost. Right now they are burning a lot of money to convince people it's good. But they might not be able to keep it up forever and need to increase prices (which few will want to pay) or degrade the quality to save money.